atheism

noun7

1. •
   A non-belief in deities.
2. •
   Belief that no deities exist (sometimes including rejection of other religious beliefs).
3. •
   A lack of belief in deities, or a belief that there is insufficient evidence to believe in a god.

   • ...but Atheism per se simply means, not denial, but rejection, in the sense of not accepting the Theistic theory of the universe which Mr. Lee has put forward tonight. — 1896
4. •
   Absence of belief that any deities exist (including absence of the concept of deities).

   • What can parents do, and mothers more especially, […] with regard to the atheism that is natural to all the children of men? — 1829
5. •
   (nonstandard) A rejection of all religions, even non-theistic ones.

   • Some worldviews are based in a belief in God; others are not. Buddhism, Taoism, atheism, Marxism, and existentialism are examples of worldviews that are nontheistic. — 2009
6. •
   Neglect of one's obligations to God; behavior incongruent with belief in God (regardless of belief in the strict sense).
7. •
   (rare, historical) Absence of belief in a particular deity, pantheon, or religious doctrine (notwithstanding belief in other deities).